Tumour-to-tumour metastasis: breast carcinoma to an olfactory neuroblastoma

Abstract

Tumour-to-tumour metastasis is a rare phenomenon. It occurs when a primary tumour is a recipient of a separate tumour within the same individual. We present a case of a 66-year-old woman with known breast cancer who presented with one-sided nasal symptoms. Examination and imaging revealed a unilateral polyp arising from the skull base. She underwent endoscopic polypectomy with the histology demonstrating tumour-to-tumour metastasis from a breast carcinoma to an olfactory neuroblastoma, a rare sinonasal tumour. Clinicians should be cautious of distant metastases in any patient presenting with head and neck symptoms and a known primary tumour. This is the first documented case of this type.

Keywords: Breast cancer; Metastases; Nasal polyp; Olfactory neuroblastoma; Tumour-to-tumour metastasis.

Figure 1

Computed tomography (coronal) of the sinuses showing a large right polypoidal mass arising from skull base.

Figure 2

a) Large polyp in right superior nasal cavity b) Partial dissection of polyp in right nasal cavity.

Figure 3

a) Postoperative computed tomography (coronal) and b) magnetic resonance imaging (axial) with well-aerated nasal cavities and no evidence of residual nasal mass.

Figure 4

Computed tomography (axial) taken 10 years prior to nasal symptoms during breast cancer staging.